Electric switch



1953 J. H. WILLIAMS ETAL 2,628,293

I ELECTRIC SWITCH Filed Jan. 9. 1952 INV NTORS.

Patented Feb. 10, 1953 UNITED STATES PATENT ELECTRIC SWITCH John. H.Williams, Barringion, and Edward J. Mastney, Berwyn, Ill., assignors toOak Mfg. 00., a corporation of Illinois Application January 9, 1952,Serial No. 265,584

2 Claims.

This invention relates to an electric switch and particularly to aconstruction for operating a rotary switch through a predetermined angleof movement.

In certain types of apparatus, particularly portable radio receivers ofthe type adapted for operation either from a battery or from a powerline, it is customary to provide a switch construction for changing fromone type of operation to the other. Such receivers have a line cordterminating in a conventional two-prong plug which may be inserted intoa conventional wall-type socket for connection to a 110 volt power line.When the receiver is to be used on battery, the line plug is insertedinto a special receptacle by the receiver. This receptacle includes aswitch which is operated by one of the prongs of the plug to change theinternal circuits of the receiver so that battery operation is possible.

This invention provides a construction which is an improvement upon suchswitch mechanism.

In order that the invention may be understood, it will be explained inconnection with the drawing wherein:

Figure 1 is a side elevation of a construction embodying the presentinvention, an operating plug being shown ready for insertion into theswitch;

Figure 2 is a front view on line 22 of Figure 1;

Figure 3 is a side view similar to Figure 1 but showing the mechanism ina different position with the plug fully inserted;

Figure 4 is a top view along line 4-4 of Figure 3.

The construction embodying the present invention has frame generallyindicated by numeral I!) and consisting of front portion II and sideportions I2 and I3, respectively. Front portion II of the frame isprovided with slots I5 and I3, these slots being transverse to the longdimension of front portion II and being spaced and dimensioned toaccommodate prongs I8 and I9 of plug 2%.

Slot I6 and prong I9 have no function as far as switch operation isconcerned. It is understood that it is immaterial which particular prongof plug 2!] is used, since the construction is not polarized. Thus, plug29 may be turned around so that prong I9 simply refers to the lowerprong.

Slot I5 has the right portion thereof, as seen in Figure 2, enlarged toform a transverse slot 2|, slots I5 and 2| together forming a generallyT-shaped composite slot.

Part I2 of the frame extends for a sumcient distance to provide part 23for supporting one end of a short stub shaft 24 forming part of a rotaryswitch. Part 23 of the frame also has car 25 to which may be anchoredone end of coil spring 26.

Rigidly attached to stub shaft 24 is switch operating member 21consisting of an irregularlyshaped piece. Member 27 has ear 28 forsupporting the hooked end 29 of coil spring 26. The other end of coilsprin 25, indicated by numeral 3|, is looped over car 25 so that thecoil spring biases part 2? to the position shown in Figure l.

Member 2'! has edge portion 32 term nating in tip port on 33 bearingagainst in-ide surface 34 of front portion I I of the frame. It isunderstood that coil spring 3'! presses member 2! so that tip 33 is inthe position shown.

Part I3 of the frame is large enough to support stub shaft 24. As seenin Figures 2 and 4, member 2! is disposed between sides I2 and I3 of theframe. Thus, actuating portion 32 and tip portion 33 of member 21 comesbehind slot I5 and is normally engaged by prong I8 of the plug wheninserted. Member 21 has concave part 35 adjacent to actuating portion 32so that when prong I8 is inserted, the tip of the prong will ride alongactuating part 32 of member 21, this actuating part functioning as a camsurface and finally permits the tip of prong I8 to enter concave region35 of member 21. In this position, as shown in Figure 3, member 21 hasbeen turned again"t the bias of spring 30 counter-clockwise through apredetermined angle, and member 21 and the prong will be stable.

Secured to stub shaft 24 is portion 3'! of a 1'0- tary switch sectiongenerally indicated by numeral 38. Switch section 38 has stator 39rigidly secured to the frame as by staking ears 40 and II extending fromside I3 of the frame. Switch section 3'! may be of any desiredconstruction and is conveniently one section of switch as disclosed, forexample, in Patent 2,186,949, issued on January 16, 1940. Instead of oneswitch section, a plurality of sections may be provided.

The particular switching arrangement and contact arrangement in theswitch section is not important, as far as this invention is concerned.However, such switch sections have appreciable drag and thus the entireactuating mechanism for the switch presents a substantial load uponprong I8 of the plug. As is well known, most plugs have prongs I8 and I9disposed in a rubber molding or in a suitable flexible mount so thatsome play of the prongs is permitted.

The tendency of one prong to move with respect to the other prong thusmakes it difficult for a plug of this character to operate the mechanismso far described. In order to support prong I8 against displacement fromthe desired path of travel during switch operation, side I3 is punchedout to provide strips AI and 42 generally extending toward each other,as seen in Figure 2, but having the opposing edges spaced from eachother to provide a gap. The gap between supporting members AI and 42 issubstantially equal to the width of slot l5 and permits prong [8 toslide between these two supporting members.

As is evident from Figures 1 and 3, supporting members 4! and 42 extendfor a substantial distance along side l3 in back of front part I l ofthe frame so that the major portion of the length of prong I8 issupported against movement toward or away from prong l9. Thus the loadupon prong l8 will have no tendency to bend or damage the actuatingprong of the plug upon insertion into the switch mechanism.

It is understood that the frame and the various parts thereof, such asthe sides, spring and the like, are made of steel or other sheet metal.

What is claimed is: 1. A switching mechanism comprising a rigid saidframe, said member having a cam portion movable with member rotation toand from the rear surface of the front part of the frame, spring meansfor biasing said member so that the cam portion is at the rear surfaceof the front portion of said frame, said cam portion lying rearwardly inline with said slot, and spaced supporting members carried by one ofsaid frame side portions, said supporting members extending rearwardlyof the front frame portion and forming a channel which is a prolongationof said slot whereby a pronged member inserted into said slot to engagethe cam portion for turning said member will have support, switchingmeans having stationary and movable contact portions, means for securingthe stationary contact portion to said frame and means for coupling saidrotary member to said movable contact portion.

2. The structure according to claim 1, wherein said member has a cut-outadjacent the cam surface into which the prong end may rest when theprong is fully inserted.

JOHN H. WILLIAMS. EDWARD J. MASTNEY.

No references cited.

